Powdering device

ABSTRACT

A powder device comprises a powder container which is formed as an exchangeable container mounted on a container receptacle via a quick-connect means. The inside of the powder container has a dome which extends from the output flow opening into the inside of the powder container. This loosens up the powder and prevents it from adhering to surfaces.

BACKGROUND OF THE INVENTION

The invention concerns a powder device for powdering printed sheets,comprising a powder container containing powder and from which powder isextracted, wherein the powder device is designed as an exchangeablecontainer which can be removed from the powder device and which has anopening at its lower end which can be closed by a closing element.

There are a plurality of conventional powder devices of this kind. DE 2252 474 A discloses e.g. a supply container for powder, wherein the loweropening forming the outlet can be closed by a ball. Containers of thistype have, however, the essential disadvantage that they are relativelyeasily blocked, since the powder sticks to the side walls or powderbridges are formed thus preventing further supply of powder from above.GB 15 88 393 B discloses a container having an elastic bottom which ismoved via a vibrator. The powder is not drawn off from this containervia a lower flow opening, rather suctioned off using a suction air flow.This also has the above-mentioned disadvantages, since the powderadheres, in particular, to the walls and can no longer continue to flowtowards the suction nozzle. U.S. Pat. No. 4,051,981 discloses a powderdevice having a bellows-like supply container, opening into apin-cushion from which powder can be blown into a blowpipe bycompressing the supply container. This device prevents sticking orformation of powder bridges, since the supply container is continuouslyelastically deformed.

DE 38 11 309 also discloses a supply container for powder, wherein thelower outlet opening is closed by a ball. When powder is required, theball is pushed into the supply container by an actuating element toloosen up the powder located above the ball which can then flow past theball in the direction of the outlet opening. Compressed air is blowninto the supply container to further loosen up the powder. The containermust be sealed in an air-tight manner to prevent the powder fromescaping from the supply container.

It is the underlying purpose of the invention to provide an exchangeablepowder container which reduces powder build-up on the container wallsand which reduces powder bridge formation in the container.

SUMMARY OF THE INVENTION

This object is achieved in accordance with the invention by a finger ordome extending into the inside of the container above the outflowopening.

The lower end of the powder container in accordance with the inventionhas an outflow opening for discharge of the powder. A finger-like domeis disposed above this outlet opening and is rigidly connected to thepowder container. This dome protrudes into the powder in the containerto substantially prevent formation of bridges and columns in the powdercontainer and to effect uniform flow of the powder. The vibrationsoccurring during operation normally cause sufficient shaking of thedome, via the powder container housing, to loosen up the powder andmaintain free flow thereof. This also prevents sticking of the powder tothe inner walls of the container.

With containers having a truncated cone-shaped lower end passing overinto the outflow opening, the dome preferentially has a length or heightwhich is greater than or equal to the length of the truncated cone. Thecritical area in which the powder is usually compressed, is therebypenetrated by the dome to assure loosening of the powder in this area.

In an advantageous embodiment, the dome has the shape of a sleeve. Thedome thereby has a vertical longitudinal axis and extends, inparticular, along the axis of the powder container. The sleeve shape hasthe substantial advantage that the powder can flow through the domeitself. Towards this end, the dome has several transverse bores forpassage of the powder into the dome. Powder flow into the dome leads toadditional loosening up of the powder supply. The powder in the dome isdischarged via the outlet opening. The dome is preferentially disposedsuch that the powder must initially flow into the dome before reachingthe outlet opening.

Advantageously, the upper side of the dome has a pointed tip at the endof the upper side of the dome for distributing the powder, inparticular, for breaking-up powder clots located above the dome.

Advantageously, the dome extends over 10% to 80% of the height of thepowder container. The dome can thereby be disposed in the container inan exchangeable fashion. This permits e.g. use of different dome designsfor different types of powder.

In a further development of the powder container, the closing element isformed as a flap extending away from the output flow opening. This flapcloses the container opening from the outside and is withdrawn when thepowder container is opened. This has the essential advantage that thepowder in the container is not additionally compressed when the powdercontainer is opened and relatively little force is required to open ormove the flap. When the container is opened, it can be easily closedagain by seating the flap on the outflow opening.

In one embodiment in accordance with the invention, the flap issupported pivotably, in particular, on the powder container. It is alsofeasible to design the closing element as a slide element which opensthe container opening via a sliding motion.

The flap is preferably disposed on the opening under the force of arestoring spring, wherein the spring force closes the opening. Thespring force is thereby sufficiently large that the flap does not openunder the weight of the powder. Moreover, the flap prevents outflow ofpowder, in particular when the container is replaced or filled.

In a preferred variant of the invention, the flap can be actuated bymeans of a drive. This drive is disposed at the powder containerreceptacle and is designed, in particular, as a tappet drive. Otherdrives are feasible, e.g. magnetic drives, pneumatic or hydraulic drivesor the like.

In one embodiment, the flap comprises a spherical body for sealing theopening of the container. This has the essential advantage that theopening can be sealed to an optimum degree and the discharged powder caneasily flow around the flap. Powder, which could impair re-sealing ofthe container, does not remain on the flap.

Preferably, the powder device comprises a quick-connect means forsecuring the powder container. This quick-connect means facilitates easyand fast removal of an empty powder container from the powder device foreither re-filling or replacement with a full powder container. Theremoval or mounting of the powder container can be done without tools.

Improved loosening of the powder within the container via the dome canbe effected by connecting the powder container to a means for setting itinto vibration, in particular a vibrator. This vibrator may be operatedeither continuously or in defined intervals. The vibrator may therebycomprise e.g. a counterweight or a magnetic oscillator.

Further advantages, features and details of the invention can beextracted from the dependent claims and the following detaileddescription of a particularly preferred embodiment with reference to thedrawing. The features shown in the drawing, recited in the claims, anddelineated in the description may be essential to the invention eitherindividually or collectively in arbitrary combination.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a side view of an exchangeable container inserted into thecontainer receptacle;

FIG. 2 shows a longitudinal section II—II, according to FIG. 1, throughthe exchangeable container; and

FIG. 3 shows a view III onto the container receptacle in accordance withFIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a container receptacle 1 for an exchangeable container 2containing powder. The container receptacle 1 is shown in a longitudinalsectional view. A funnel-shaped connecting piece 3 is disposed below thecontainer receptacle 1 which opens into an intermediate container 4 madefrom an elastic material e.g. rubber or the like. The containerreceptacle 1 and the connecting piece 3 are mounted to a mounting plate5.

A vibrator 6 is mounted to the container receptacle 1 for vibrationthereof. The vibrator 6 contains an oscillator driven via magneticforces. The vibrator 6 may thereby be driven continuously, inpredetermined time intervals, or as required.

The container receptacle 1 comprises an annular radially inwardprojecting receiving shoulder 7 onto which the exchangeable container 2is disposed. A receiving shoulder 7 pin 8 thereby engages into anopening 9 (FIG. 2) disposed in the exchangeable container 2. The opening9 is located at a funnel-shaped container neck 10, in particular, at anannular attachment 11 seating precisely within the annular receivingshoulder 7. This attachment 11 is furthermore provided with a radiallyextending opening, disposed, with respect to the longitudinal axis 13 ofthe exchangeable container 2, opposite to the opening 9. A spring-loadedpin 14, borne for displacement, engages in this opening 12. This pin 14is disposed on a tensioning knob 15 for radial withdrawal from theopening 12. The exchangeable container 2 is thereby fixed in thecontainer receptacle 1 via the two pins 8 and 14.

The upper end 16 of the container neck 10 maps into a container housing17, closed by a lid 18. The upper end of the exchangeable container 2must not be air-tight. The lower end 19 of the container neck 10 has anoutflow opening 20 through which the powder contained in theexchangeable container 2 can flow out of the container in a downwarddirection. A dome 21 is inserted into the outflow opening 20 and extendsupwardly in the direction of the longitudinal axis 13, i.e. into theinside of the container. The outflow opening 20 is closed by a flap 22supported for pivoting about an axis 23. The axis 23 is located at aprojection 24 of the container neck 10 and supports a pivoting lever 25in a rocker-like manner which can be actuated at the upper end via atappet drive 26. The other end is offset and comprises a sphericalsealing body 27 at its free end which closes the outlet opening 20 fromthe outside. When the tappet drive 26 actuates the pivoting lever 25(dotted lines), the spherical sealing body 27 moves away from and opensthe outflow opening 20 it so that the powder can flow out.

The dome 21 disposed in the outflow opening 20 is formed by a sleeve 28having four transverse bores 29 distributed about the circumference anddisposed in four stacked planes. The upper end of the dome 21 is closedwith a pointed tip 30. The powder contained in the exchangeablecontainer 2 thereby flows through the transverse bores 29 into thesleeve 28 of the dome 21 and exits same downwardly into the intermediatecontainer 4 when the outflow opening 20 is open.

As shown in FIGS. 2 and 3, the container receptacle 1 is borne by a pin32 for pivoting about a vertical axis 31. A stable seating position ofthe container receptacle 1 is assured via two horizontally supportedpressure springs 33 interposed laterally next to the pin 32 between themounting plate 5 or a retaining angle 34 and the container receptacle 1.The vibrator 6 thereby generates vibrational motion to shake thecontainer receptacle 1 about the axis 31. The powder in the exchangeablecontainer 2 is loosened up by the dome 21 and maintained in a pourableor sprayable state.

As shown in particular in FIG. 3, the horizontal longitudinal axis 35 ofthe vibrator 6, corresponding to the direction of motion of anoscillator, is perpendicular to the axis of oscillation 31 of thecontainer receptacle 1 and is disposed at a distance therefrom such thatthe container receptacle 1 is shaken when the vibrator 6 is active.

What is claimed is:
 1. A powder device for powdering printed sheets, thedevice comprising: an exchangeable powder container having an opening ata lower end thereof; a closing element cooperating with said containerto close and open said opening; and a dome disposed within saidcontainer above said opening to extend from said opening into an insideof said container, wherein at least one of said container and the powderdevice comprise means for removing said container from the device. 2.The device of claim 1, wherein at least one of said container and thepowder device comprise means for removing said container from thedevice.
 3. The powder of claim 1, wherein said dome is sleeve-shaped. 4.The powder of claim 1, wherein said dome has a vertical, longitudinalaxis.
 5. The powder of claim 1, wherein said dome has a plurality oftransverse bores through which powder can flow into said dome.
 6. Thepowder of claim 1, wherein said dome has a pointed tip at an upper endthereof.
 7. The powder of claim 1, wherein said dome extends through 10%to 80% of a height of said powder container.
 8. The powder device ofclaim 1, wherein said container has a neck at a lower portion thereof,said neck tapering a container wall in a direction toward said opening.9. The powder device of claim 8, wherein said dome extends beyond aheight of said neck.
 10. The powder device of claim 1, wherein saidclosing element comprises a flap extending away from said opening. 11.The powder device of claim 10, wherein said closing element comprisesmeans bearing said flap for pivoting.
 12. The powder device of claim 10,wherein said closing element comprises a spring for urging said flap toclose said opening.
 13. The powder device of claim 11, wherein saidclosing element comprises a spring for urging said flap to close saidopening.
 14. The powder device of claim 10, wherein said flap is borneon said powder container.
 15. The powder device of claim 10, furthercomprising drive means communicating with said flop to open and closesaid opening.
 16. The powder device of claim 15, further comprising acontainer recepticle for holding said container, wherein said drivemeans is mounted to said container receptacle.
 17. The powder device ofclaim 15, further comprising a housing having a container recepticle forholding said container and a downwardly extending connector member,wherein said drive means is mounted to said connector member.
 18. Thepowder device of claim 10, wherein said flap comprises a sphericalsealing body for said opening.
 19. The powder device of claim 10,wherein said flap closes a lower end of said dome.
 20. The powder deviceof claim 1, wherein said removing means comprises a quick-connect meansfor releasing, by hand, said container from the device.
 21. The powderdevice of claim 20, wherein said quick-connect means comprises atensioning knob and a pin.
 22. The powder device of claim 1, furthercomprising means for vibrating the powder device.